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    <script>
        // 1. 求 1~100的累加和
        var sum = 0;
        for (var i = 1; i <= 100; i++) {
            sum += i;
        }
        console.log(sum);

        // 2. 求 10~50的累加和
        var sum = 0;
        for (var i = 10; i <= 50; i++) {
            sum += i;
        }
        console.log(sum);

        // 3. 函数就是封装了一段可以被重复执行调用的代码块 目的： 就是让大量代码重复使用
        function getSum(num1, num2) {
            var sum = 0;
            for (var i = num1; i <= num2; i++) {
                sum += i;
            }
            console.log(sum);
        }
        getSum(1, 100);
        getSum(10, 50);
        getSum(1, 1000);
    </script>
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